MSIL .netmodule or module compiled with /GL found

I get the following warning when linking against a custom static lib in a release build:

Quote:

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mystat.lib(mystat.obj) : MSIL .netmodule or module compiled with /GL found; restarting link with /LTCG; add /LTCG to the link command line to improve linker performance

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Both the project and the static lib are compiled as release (\GL).

Quote:

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#pragma comment(lib, "mystat/x86/Release/mystat.lib")

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So what could be the cause of this warnign?
Also: neither the projekt nor the static library are .net.


Sys: win xp sp3, msvc2008pro, native c++.